I don't. Interestingly with -XNegativeLiterals one can write e.g. “10 + -2” which would cause a precedence parsing error without NegativeLiterals. On the other hand, “10 -2” will cause a type inference error (“Could not deduce (Num (a0 -> t))”) with NegativeLiterals.

That "-2 ^ 2 == 4" example shows this extension is crazy! Who would want that behavior? Using the extension do you get "-2 ^ 2 == 4" and, with an extra space after the minus sign, "- 2 ^ 2 == -4"? If so, I don't want anything to do with it.